Data storage devices, such as magnetic or optical storage media, are employed to store digital information. In some instances, apparatus information relating to the status of the storage medium or the reading device is stored on the medium itself. For ease of reference in this application this type of information will be referred to as “apparatus” or “vital” or “z-track” information. Despite that shorthand definition, it should be understood the apparatus information may include information both about any of, or any combination of one or more storage devices, one or more storage media, and any other computing device.
In a known system, the medium serial number is stored on the medium, instead of on another, associated data storage device.
However, storage devices that use elements for reading and another for writing, such as read-write heads, introduce the possibility that the apparatus information is not written along the center of a track. Generally speaking it is understood this may occur because of the physical offset between the read and write elements of the read-write heads. In some cases, the apparatus information may not be written within an acceptable range of the desired medium track location, and thereby become unreadable. When this occurs, the information is lost, which can negatively affect the reliability and performance of the data storage device.
In addition, although storage devices may be calibrated to write in the same location from which they can subsequently read-back, the physical offset between the read and write elements on the read-write head make it conceivable that the vital tracks maybe over-written by neighboring tracks. Moreover, the interchanging of removable media from a data storage device can decrease the reliability of z-track reading and writing.
Therefore, there exists a need for a data storage device that can reliably record and retrieve apparatus information.